Factory oil pressure gauge fluctuates while braking

[vma1788]

Long time lurker, first time poster.

69 c10 with factory cluster. While braking the oil pressure gauge drops. Under, relative, hard braking it will drop all the way down. No audible knocking, oil level good with not old VR1 20w50.

Is this just an overly sensitive gauge? Doesn't really make sense unless its just the slosh and the sending unit temporally goes dry?

Old pic, pre wheel change now on 15x8 rallyes.